The invention concerns a method for machining the interior of a brake caliper of a disc brake on which are formed: a first caliper portion on the one side of the brake disc of the disc brake; a second caliper portion on the other side of the brake disc; and a bridge portion connecting the caliper portions and providing a free space for at least a part of the brake disc. At least one of the caliper portions is provided with a cavity for receiving a brake application device, which cavity comprises a mounting opening towards the free space and extends in the opposite direction as far as a caliper rear wall, on the inner side of which at least one support surface is formed for the forces acting during the brake application, wherein the machining of the support surface is carried out from the free space, and for this purpose, a tool is brought into the cavity from outside the brake caliper. Such a brake caliper is composed of a caliper portion on one side of the brake disc of the disc brake, a caliper portion on the other side of the brake disc, and a bridge portion which connects the two caliper portions and, when the disc brake is mounted ready for use, bridges the disc brake on the outside and provides a free space into which the brake disc of the disc brake at least partially protrudes. At least one of the two caliper portions has a cavity with an opening pointing towards the free space, wherein a brake application device is located in the cavity.
Such brake calipers are known in the prior art both as a one-piece or integral design, and also as a multipiece design. In principle, the multipiece design has the advantage of offering easier access to individual brake caliper regions for machining, e.g. by means of boring or milling tools. Above all, with the multipiece design, cavities in the brake caliper can be reached relatively easily during production, as can the connecting surfaces at which the individual caliper parts are then joined together, e.g. by corresponding bolt joints. This connection is however also disadvantageous since the caliper parts must be connected together with a precise fit in a separate assembly process.
The problems of assembly and fit do not arise with a one-piece brake caliper. However, the one-piece design restricts the possibilities of accessing certain locations, above all in the cavities of the brake caliper housing, by means of boring or milling tools. The surfaces in the interior of the brake caliper which must always be machined include support surfaces which receive the forces acting on application of the brakes. Thus, for example, brake calipers for disc brakes are known in which, to increase the force, a lever is arranged in the cavity of the brake caliper and bears pivotably against the caliper rear wall of the brake caliper which is formed correspondingly stable. Machining by material removal is usually essential at this bearing site.
For machining such support surfaces, DE 195 15 063 C2 discloses introducing the machining tool into the interior of the caliper through a specifically provided working opening on the side of the caliper. The disadvantage with this working opening is that it serves solely to guide the machining tool through, while in operation of the disc brake the opening has no purpose.
In the brake caliper described in DE 10 2007 001 960 A1, again a tool for machining the portion faces is introduced into the interior of the brake caliper through openings present on the side of the brake caliper housing, in order to machine the support surfaces situated therein. These openings however have an additional function. They are not merely working or mounting openings, but also serve as support bearings for a bolt which is part of the brake application device.
According to EP 1 881 472 A1, a further one-piece brake caliper is provided with a machining opening which is aligned to a hydraulic actuating cylinder for machining of the actuating cylinder. This opening is configured as a type of recess and is situated in the opposite caliper portion of the brake caliper arranged on the other side of the brake disc.
The generic EP 2 304 261 B1 discloses a method for producing an integral brake caliper, in which the brake caliper without an additional working opening is produced. The only opening is the mounting opening of the brake caliper which is open towards the brake disc and through which the application device can be mounted. A tool holder with tool arranged thereon can be moved through this opening into the cavity of the brake caliper. For this movement, since the tool holder is L-shaped and the bridge portion is relatively short in the caliper longitudinal direction, a superposed movement sequence is required, wherein the tool holder either initially performs a rotation about a virtual axis lying in the brake caliper plane and then performs a straight movement, or the tool holder first performs an obliquely angled and then a straight movement. Superposed movement sequences require corresponding movement options. Each movement option is however associated with a further bearing play, which may adversely affect the precise machining of the support surfaces.
The invention is therefore based on the object of creating a method for machining the interior of a brake caliper of a disc brake which allows high-precision machining of the support surfaces in the interior of the brake caliper even under the constricted spatial conditions typical for machining of a one-piece brake caliper.